Oxide backplanes have attracted wide attention for their excellent performance. However, the performance of oxide backplanes are sensitive to factors such as heat and light, and this problem is even more prominent for an AMOLED display screen made of an oxide backplane. Since an active-matrix organic light-emitting diode (AMOLED) is driven by current, the temperature of the oxide backplane will easily rise during lighting, which influences the performances of the oxide backplane and thus gives rise to problems such as decreased display brightness, a shortened service lifetime and large-size unevenness of display brightness.